Rheostat



3 Sheets-Sheet 1 wv Em (3110011 fo'c L. KEBLER RHEOSTAT Filed April 8, 1920 L. KEBLER RHEOSTAT Filed April 8, 1920 3 Sheets-Sheet 2 wwQ Feb. 17. 1 25- 1,526,708

L. KEBLER RHEOS TAT Filed April 8, 1920 3 Sheets-Sheet 5 Patented Feb. 17, 1925.

UNITED STATES LEONARD KEBLER, 0F B RONXVILLE. NEW YORK, ASSIGNOR TO WARD LEONARD ELECTRIC OOMPANY, A CORZPORATIO'N OF NEW YORK.

BEEOSTAT.

Application filed April 8,

To all whom it may concern:

Be it known that I, LEONARD KEBLER, a citizen of the United States. residing at Bronxville, in the county of Vestchester and State of New York, have invented certain new and useful Improvements in Rheostats. of which the following is a specification.

This invention relates to rheostats having a series of contacts with adjustable means for controlling the resistance in the circuit as desired. It more particularly relates to regulating rheostats adapted to be mounted upon a panel or other suitable sup- )ort. 1 One object of the invention is to provide a construction of units adapted to be built up and added one to the other to provide a total number of units for securing the degree and character of control desired; and to accomplish this by a simple construction which may be utilized and assembled by the manufacturer or the user. A further object is to provide a construction which is adapted to be mounted upon the front or the back of the panel board without change in the construction of the rheostat so that the same device may be sold and purchased for either character of-mounting. Another object is to provide a construction which may be used either as an open or enclosed type, as desired, using the same rheostat units in either case.

Other features of my invention include the provision of a terminal block for each rheostat unit with provision for the leads as required for one or more units and the connections between them; also to avoid the use of an auxiliary stop for the contact arm by causing the terminal block to also serve as a stop. Another object is to insure the shaft of each unit being dead and insulated from all parts. Another object is to provide an improved character and form of contact means and its mounting in the contact arm with a View to securing simplicity in construction and assembly and a high degree of contact.

Another object is to provide a simple form of coupling between units and of a character that will permit adjustment so' that the movable contacts will all be aligned, or make contact on their respective units which will properly correspond With the 1920. Serial No. 372,150.

contacts made at the same time on other units. Another object is to provide a scale and pointer of simple construction for indicating to the user the adjustment secured or, if desired, showing the motor' speed which corresponds to any particular adjustment; and to so construct the scale and pointer that it may be conveniently used or removed without the necessity of change in the structure of other parts.

Another important object is to provide. a construction for readily' permitting proper alignment of the shaft so that it will be perpendicular to the plane of the faces of the fixed contacts so as to insure a uniform contact of the contact shoe therewith in all positions of adjustment. These and other objects and advantages of my invention will be understood from the following description and accompanying drawings illustrating a preferred embodiment thereof.

Fig. l is a vertical section illustrating two units assembled and enclosed and mounted on the back of the board. Fig. 2 is arear elevation of one of the rheostat units detached. Fig. 3 is a front elevation of the center bearing of a unit detached. Fig. 4 is a rear elevation of the same. Fig. 5 is a front elevation of the central portion of the plate of a rheostat unit-which receives the center bearing. Fig. 6 is a sectional view of the coupling between the movable elements of two rheostat units. Fig. 7 is a front elevation of a scale plate detached. Fig. 8 is a side elevation thereof. 9 is a front elevation of the pointer detached. Fig. 10 is a side view thereof. Fig. 11' is a side view showing one unit enclosed and mounted on the front of the board, and Fig. 12 is a side elevation showing two units mounted on the front of the board and not enclosed.

The rheostat unit is especially adapted for readily being mounted upon the face or back of the board and for being assembled one behind the other to any extent desired. In the particular construction here illustrated, it comprises a sheet iron plate 1 having a turned up outer edge or rim 1. The inside of the sheet iron plate is covered with a coating of insulating material upon which is located the resistance connected .to a series of circularly arranged contacts 2. The resistance elements are covered with a coating of vitreous enamel but as this construcner face of the bearing block rim are retion of the resistance element and arrangecessed portionslO angularly spaced from ment of the fixed contacts forms no part the cut away portions 9. The scale plate of the present invention, it need not be parwhich is adapted to be carried by the bear 7', which enters theupper 'hole 6.

ticularly referred to and of course other ing block is shown in Figs. 7 and. 8. It consuitable construction might be used. 7 The sists of a sheet metal ring 11 dished as inresistance plate has a central circular opendicated in Fig. 8. The plate has three ining,'in which three sector shaped extenslons Wardly extendmg tongues 11, which are 1";extend spaced apart equally as shown spaced to correspond with the cut-away in Fig. 5. These extensions are integral portions 9 of the bearing rim and are adaptwith the iron plate and bendable relatively ed to pass through these cut-away portions to each other in or out for the purpose herewhen the scale plateis placed over the bearinafter explained, m'g block. The scale plateis then turned A center bearing 3 preferably of molded angularly, the tongues 11' being pressed ininsulating material carries the shaft 4 of wardly so as to permit themto pass under the movablelcontact arm. This center bearthe rim of the bearing block until they dome ing fits within the plate 1 and is secured to respectively opposite the recesses 10. They the extensions 1". It has three sector then snap outwardly to seat in these recesses shaped inner extensions 3' which loosely; fit' and securely lock the scale plate in place and extend through the sector shaped openon the bearing block as shown in Fig. 11. ings of plate 1 between the extensions 1". In caseswhere the rheostat is mounted on The recesses in the bearing block- 3 receive the back of the panel board as shown in the extensions 1", which engage the bottom Fig. 1, the plate 12 which is secured to the of these recesses, the bearing block being o r y sc ews i lmllarly providedwlth secured to these extensions by screws and an under-cut rim. and cut-away portions 9 nuts 5, the screws passing through holes 5 and recesses 10 so. that the scale plate 11 in the bearing block and having their heads may be slmllarly apphed to the plate 12 counter-sunk in the face ofthe block and h n eslrei' engaging nuts 5" on the inside of-the eg- The handle 13 0f the rheostat shown in tensions 1". Figs. 1 and 11 is preferably of molded insula- .This support of the bearing block on the tion having an inner hole to receive the central extensions .of' the plate, which-exshaft of h rheostfit and held in pl ce tensions are somewhat flexible and bendable, thereon by a central screw 14.-. The shaft repermits the bearing block to be adjusted by ceives a cotter pm which is located in a tilting it andcorrespondingly bending the cross-wise recess 13 in the. inner end of the extensions 1" until the axis of the shaft 4; handle nd e f i y locks the handle is perpendicular to the plane of the face of to e Shah?- T Pointer 16 for S0316 the resistance contacts 2, the extensions 1" P IS Shown 111 Q 9 and l n ha 51 being sufliciently stifl' to. retain th i fi l central opening 16 through which the shaft position of adju t nt i l t use f th of t he rheostat passes and has lateral prodevice. This insures a uniform contact of l f Which extend into the ends f the contact shoe with the resistance con-' the TeCeSQ the h ThuS w en tacts in all angular o iti of th t t the handle is secured to the rheostat shaft arm, It; will b n t d th t th i f th it also locks in place the pointer 16 bet ween bearing block is undercut somewhat to perthe Inner F 0f the handle a the Plate il; ffi i t, I dj t t tilti f. th .12 or hearing block 3 as the case may be as block to give the required alignment of the ShOWIl 1n F gS. 1 and '11. shaft.- The inner end. of the rheostat shaft 4 has In therear face of each extension 3 of a flattened knurled head 4'. The contact the bearing block is formed a hole 6. A arm 17 is of molded insulation molded about contact ring 7 is carried on the inner face/of the head 4' of the shaft and thus securely the bearing block and has three extensions fixed thereto. The contact shoe 18 carried 7 which are received respectively by the by the contact arm is of sheet metal with three holes 6, which thus serve to ositi'on two strips 18 integral therewithbent at contact ring 7 and which is held against the right angles to the plane of the shoe and bearing block by the pressure of the contact extending into a hole 17 in the contact arm shoe. vThe upper extension '3' of the block and in a recess 17 at the 0nd of the conhasformedtherein the opening 6' which tact arm. The contact shoe is thus carried connects with the upper hole 6 and serves by the arm in its movement, but is freely as a pathway for the terminal lead 8 which movable so as to make good electrical enis electrically connected with the ring 'congagement with the fixed contacts. Formed tact 7 by means of the tongue or extension in the contact arm is a rectangularly shaped recess 19 inwhich is seated a spring 20. The run of the bearing block has cut Thisspring is preferably formed as shown away portions as shown at 9 and on the i inFig. lhaving one leg engaging the contact recess 15) where it seats and forms a coil go.

and then continues to the inner end of the recess and forms another coil 2 from which the other end or leg of the spring extends outwardly to engage the contact shoe over or near the fixed contacts 2. This simple form of duplex coil spring with oppositely extending legs thus causes the contact shoe to be pressed against the fixed contacts and the ontact ring so that in all positions a. good electrical contact between the parts is obtained and the contact shoe is permitted to ride over and adapt itself to any unevenness in the contacts. This assemblage of the contact shoe and spring in the contact arm also permits the parts to be readily placed in position. The rheostat shaft has a circumferential groove engaged by a spring clip 21 at the face of the hearing block and thus retains the rheostat shaft in fixed position axially and gives the required pressure to the contact arm and spring upon the movable contact against the fixed contacts. The spring clip 21 is U-shaped and permits the shaft to be easily removed when desired by merely forcing the spring clip out of the groove in the shaft.

The terminal block 22 is mounted at the top of each rheostat unit at the back of the plate and is preferably of porcelain or molded insulation of the form shown in Figs. 1 and 2. It is shown as having two side extensions 22 which are perforated to receive the terminal screws 23 and, which pass ra dially through the extensions 22' to receive nuts 23. which are located in recessed slots on the outer face of the extensions. The terminal block is secured to the back of the rheostat unit by a central screw 24 which passes through the plate 1 and engages a nut 2-1: seated in a slot upon the back of the terminal block. On the front face of the terminal block is a circular groove 25 which is opposite a hole 26 through the rheostat plate. the groove 25 forming a passage for leads when desired. which enter through the hole 26 and pass through the groove 25-out through the bottom of the terminal block and then connected to the terminals on the block. In case the hole 26 and groove 25 is not used for this purpose, the hole 26 is conveniently covered by a plate 27 such as the name-plate of the manufacturer, which is held in place by the screw 24. The terminal block 22 also has a depending projection 28 which extends into the path of the contact arm 17 and thus serves as a stop for the contact arm in either direction of movement to prevent the operator from turning the arm beyond the initial or final resistance contact in either direction of movement.

Referring to Figs. 1 and 2, it will be seen that the rim 1 of each rheostat unit is perforated in this example at three equi-distant points, through which pass screws 29 having nuts 29, the perforations being suliiciently near the rear face of the rheostat. plate to prevent the nuts 29 from turning when the screws 29 are turned for convenience in assembling. \Vhen a single unit is used and mounted at the rear of a panel board as shown in Fig. 1. supports 30 are used. which are preferably of sheet metal bent in the form of a trough for stiffness and having outwardly extending portions 30' bent at right angles and slotted to'recei\'e screws 31. which pass through the panel board and having nuts 31', which engage the extensions 30'. The outer end of the supports 30 have slotted extensions 30" adapted to receive the screws 29. The outer end of each shaft 4 of the rheostat unit is tapped to receive a central screw for retaining the bandle coupling and likewise drilled on a diameter to receive a cotter pin. Vhere the unit is mounted on the back of the board. a coupling sleeve 32 is connected to the rheostat shaft 4. by a cotter pin 33 and to an extension shaft 34 by a set screw 35 in the form shown in Fig. 1. In case the unit is mounted on the front of the board, the sleeve 32 and extension shaft 34 is not used and the handle 13 is mounted directly on the rheostat unit shaft 4 as shown in- Fig. 11. the handle 13 being attached directly to the shaft 4 by the central screw 14 and a cotter pin 15 being passed through the shaft 4 for locking the handle thereto.

In Fig. 1. two rheostat units are assem bled and are shown enclosed. The cylinder 36 of sheet metal in this case serves as the spacer and support for the second rheostat unit shown at the left of Fig. 1 and also to enclose the parts between the two units. This cylinder 36 is provided with open slots at its edges to receive the screws 29 of the two units which clamps the parts together. The second unit of Fig. 1 is enclosed by a sheet metal cylindrical box 37. the edges of which are slotted to receive and be clamped in position by the screws 29. The upper part of the box 37 above the terminal block 22 is cut-away and covered by the sheet metal auxiliary box 38 which has an extension 38 at each end. by which it is secured to the box 37. This auxiliary box 38 has a. central opening 38' at the top for receiving the incoming leads to the regulator which are. conveniently conn cted to the terminals of the terminal block already described. The electric connections between the two rheostat units may be made from one terminal block to the other by leads from the terminals of the rear terminal block passing out through the groove 25 of the rear terminal block and through the hole 26 of the rear rheostat unit directly to the terminals of the terminal block 22 of the sides of element 39. The element is further secured to the shaft by. ascrew and washer 41, 41". The outer end of coupling element 39 has two extensions or legs 39" whi'chens gage opposite sides of the outerend of contact lever 17 of the adjoining rheostat unit as indicated in Fig. 1. These legs or extensions 3 9" are bendablesidewise which affords means for sufficient relative adjustment of one contact arm of a unit to the contact arm of the unit to which it is coupled 1 -forsecuring proper alignment or relationship to give proper or desired relative con- "tact of the contact shoes on therespective units. v

In Fig. 1 only two units are shown assembled, but it is evident that the construction and relationship of the parts is such that any desired number of units can be similarly grouped together. Thus if an additional unit were to be added to the two shown in Fig. 1, another cylinder 36 would be added over the left-hand unit and a third unit with an enclosing casing 37 added at the outer end of the second cylindrical element 36. In case the units are not to be enclosed, the em closing box 37 at the rear of the last unit is omitted and the cylinders 36 are replaced by spacing strips which would be engaged by the screws 29 in the same way as the enclosing casing.

In Fig. 11 one unit enclosed is shown mounted on the front of the panel board. The same box 37, which is used for enclosing the outer unit when mounted on the rear of the board is used when mounted on the front. For front mounting the boxes 37 are provided with offset feet 42 and supported on the board as shown in Fig.- 11, the handle 13 being applied directly to the shaft 4 of the rheostat unit. Thus the same box 37 is constructed to serve as the enclosing box of the last unit for rear board mounting and for enclosing and supporting the unitnearest the board for front board mounting. It is evident that if an additionalunit were to be added to the one shown in 'Fig. 11, the handle 13 would be removed and replaced by the coupling element 39, which would engage the contact arm of the unit added in front of the one shown in Fig. 11, and the handle would be applied directly to the shaft 4 of the front unit. The enclosing cylinder 36 would serve to enclose and support the front rheostat unit from the rear unit in amanner corresponding to that shown in Fig.

1. Similarly, additional units could be added if desired.

1.52c,7os

board and unenclosed. The supports 30 previously described are mounted on the front of the board and support the first unit. The second unit is supported from the first unit by' supporting strips 43, which are engaged by the screws 29 of the first unit and similar screws 29 of the second unit. The supporting strips 43 are preferably of the same form as the supports 30, except that the extension 30' instead'of being bent atright angles is left in the plane of the support.-

The units are operatively coupled as already described, the handle 13 being applied to the shaft 4 of the front unit. Additional units could be similarly added and built up if desired.

It is evident from the above description th at I have provided a construction of rheo stat unit, and co-operating means which are adapted to be built up to any extent desired for front or rear mounting and eitheropen or enclosed. Also the various features of improvement are such as to secure simplicity in manufacture and assembling of the parts and securean efficient and durable construc tion.

Although I have described one embodiment of my invention, various modifications may be made therein without departing from the scope thereof.

I claim 1. A rheostat unit comprising a plate supporting the resistance elements, supporting elements for supporting said unit from a panel board, and means for connecting the outer ends of said supporting elements to the outside edge of said plate.

2. A rheostat unit comprising a plate supporting the resistance elements, said plate having an edge portion turned at right angles thereto, supporting elements for supporting said unit from a panel board, and means for connecting the outer ends of said supporting elements to said edge portion of, said plate.

3. A rheostat unit comprising a plate supporting the resistance elements,-said plate having a circumferential rim at right angles to the plate. supporting elements for supporting said unit from a panel board, and means passing through said rim for connecting the outer ends of said supporting elements to said rim.

4. A rheostatunit comprising a plate supporting the resistance elements, and means whereby said plate may be secured to the front or back of a panel board comprising fastening means engaging the outer edge of said plate.

5. A rheostat unit comprising a plate supporting the resistance elements, and means whereby said plate may be secured to the front or back of a'panel board comprising said casing to the edge of fastening elements at the periphery of said plate extending in a direction parallel with the plane of said plate.

6. A regulator comprising a plurality of rheostat plate units parallel to each other, means engaging the peripheries of the plates of said units for supporting and spacing said plate units one from the other, and fastening elements passing through said means for securing same to said units, said fastenin elements extending in a direction paral el with the planes of said plate unit;

7. A rheostat unit comprising a plate supporting the resistance elements and fastening means on the periphery of said plate, whereby said unit may be supported from another similar unit and also supported from a panel boar 8. A rheostat unit comprising a plate supporting the resistance elements, supports for a panel board, an

supporting said unit on enclosing casing for said unit, and fastening means for connecting said supports with the edge of said plate and for also securing said plate.

.9. A rheostat unit comprising a plate supporting the resistance elements, means for supporting said unit from the back'ofa panel board and embracing the periphery of said plate, and a casing enclosing -said unit and also embracing the periphery of said plate.

10. A rheostat unit comprising a plate having fixed cpntact-s thereon, a contactarm, a shaft supporting said arm, and means comprising bendable metal for aligning said shaft perpendicular to the plane of the face of said fixed contac i 11. A plurality of' rheostat units each comprising a supporting plate and central operating shaft, a contact lever on-each of said shafts, a handle on the shaft of the front unit, and a coupling on the shaft of an adjoining unit, said coupling engaging the contact lever of the front unit.

12. The combination of-a pair of rheostat units, each comprising an operating shaft, said shafts being in alignment with each other, a contact lever on each of said shafts, a handle on the shaft of the front unit, and a coupling onthe shaft of the rear unit and embracing the sides of the contact lever of the front unit.

13. The combination 'of two rheostat units each comprising an operating shaft in .ine with each other, and adjustable bendable sheet metal means for coupling said shafts.

14. The combination of two rheostat units each comprising an operating shaft in line with each other, and means for coupling said shafts, said means having a bendable metal-portion for shifting one shaft angularly with reference to the other.

15. The combination of two rheostat units each comprising an operating shaft in line with each other, and means for coupling said shafts comprising a bendable portion for securing angular adjustment of said shafts.

16. The combination of two rheostat units each comprising an operating shaft in line with each other, an arm on one of said shafts, and a coupling on the other of said shafts having bendable projections embracing said arm.

17. A rheostat' unit having a series of fixed contacts, a contact arm adapted to engage said contacts, a shaft for supporting said arm, and flexible means for supporting said shaft. .7

18. A rheostat unit comprising a plate having fixed contacts thereon, a contact arm, a shaft supporting said arm, and adjustable means for supporting said shaft for aligning saidshaft perpendicular to the plane of the face\of said fixed contacts.

19. A rheostat unit comprising a supportinng plate, fixed contacts thereon, a contact arm, a shaft for said arm, and a bearing of insulating material for said shaft, said plate having a flexible portion for supporting said bearing.

20. A rheostat unit comprising a plate having a series of fixed contacts circularly arranged thereon, a central shaft, a contact arm carried by said shaft, and a bearing for said shaft adjustably mounted with reference to said plate.

a 21. A rheostat unit comprising a plate, a series of circularly arranged fixed contacts supported thereon, a central shaft passing through said plate, a contact arm on said shaft,-said plate having a yieldable portion near said shaft, and a bearing for said shaft mounted on the yieldable portion of said late.

22. A rheostat comprising a series of fixed contacts, a contact arm, a contact shoe carried by said arm and engaging said fixed contacts, and a spring carried by said arm for forcing said shoe against said contacts, said spring having a spiral coil seated in a recess in said arm and having its two end portions displaced from each other and both end portions engaging said contact shoe.

23. A rheostat comprising a series of fixed contacts, a contact arm, a contact shoe carried by said arm and engaging said fixed contacts, and a spring having two spiral portions located ina recess in said arm and having an end portion extending from each of said spiral portions and having each end portion engaging said contact shoe.

24. A rheostat having a series of fixed contacts and a contact displaced therefrom, a contact arm, a contact shoe carried by said arm, and a in said arm,

said spring having two spiral portions and an end portion extending from s rin located in a recess' each of said spiral portions, one of said end portions engaging the contact shoe over said series of contacts and the other end portion engaging said shoe over said displaced contact. I

' 25. A rheostat having a. series of contacts and a contact arm, and a terminal block, said terminal block having a portion positioned in relation to said arm to'alsoserve as a stop therefor.

26. A rheostat having a series of contacts, a contact arm and a single terminal block for the terminals of said rheostat and also, having a portion extending in the path of said arm to serve as 27. A rheostat comprising a plate, a series of contacts thereon, a contact arm for engaging said contacts, a terminal block se-. cured on the hack of said plate and having a pathway for lead wires coming through said plate, said plate having an opening opposite said pathway, a cover plate for said opening, and a common means forsecuring said terminal block and cover plate in position.

:28. A rheostat comprising a series of contacts, a contact arm for engaging said conand a terminal block on said rheostat having side extensions for terminal connections and a middle extensionnn the path of movement of said arm to serve as a stop therefor.

29. A rheostat comprising a series of contacts and a contact arm, a shaft connected with said arm, a stationary element surtacts,

rounding the front portion of said shaft, a scale plate carried by said element, said scale plate having inwardly extending yieldable projections adapted to seat in undercut recesses in said element for supporting said scale plate, and a polnter carried by said shaft.

a stop therefor.

bent portion an nner recess, an element passing through said shaft and extending into the recess in said handle for locking said handle to said shaft, a scale plate, and a pointer having an angular portion also extending into said recess of the handle.

32-. A rheostat having a series of contacts,

a contact arm, a shaft therefor, a bearing for said shaft, and a scale plate carried by said bearing, said scale plate and bearing having interlocking projections and recesses, the projections on yieldable and adapted to make aspring engagement in the recessesof said bearing.

33. A rheostat having a series of contacts, a contact arm, a shaft therefor, a bearing for said shaft, and a scale plate carried by saidloearing, said scale plate having inwardly extending projections and said hearing having cutaway portions corresponding with said projections and also having recesses in which said scale plate projections seat.

34. A. rheostat comprising a resistance contact plate, a contact arm, a shaft carrying said contact arm, a bearing block for said shaft, said block being supported on said plate and having a recess in one face of said block, and a contact ring seated against said face of said block and having a projecting portion engaging said recess.

LEONARD KEBLER.

said scale plate being 

